Association between gamete source, exposure and preeclampsia: A review of literature

Table 3 Studies reporting preeclampsia and pregnancy-induced hypertension in relation to length of sexual cohabitation and use of barrier contraception

Ref.	Design	Sample size	Main outcome measures	Results
Robillard et al[7]	Retrospective cohort	1011 pregnancies	Incidence of PIH	Incidence of PIH was 10.6% (entire cohort) and 5.1% among women with > 12 mo of sexual cohabitation (11.9% and 3.3% for primigravidae, respectively)
Verwoerd et al[28]	Case control	60 cases with preeclampsia 60 normotensive controls	Length of sexual cohabitation	Unprotected sexual cohabitation of > 6 mo was a negative predictor for preeclampsia (coefficient -0.57, SE 0.62, P = 0.03)
Olayemi et al[31]	Prospective cohort	2630 pregnancies	Incidence of hypertension in pregnancy	Length of sexual cohabitation before pregnancy was protective against hypertension in pregnancy (HR = 0.96, 95%CI: 0.93-0.99) but not preeclampsia (HR = 1.07, 95%CI: 0.00-1.15)
Kho et al[42]	Prospective cohort	2507 pregnancies	Incidence of preeclampsia	OR for preeclampsia were 2.32 (95%CI: 1.03-5.25) and 1.88 (95%CI: 1.05-3.36) for short sexual relationship of less then 3 mo and less then 6 mo respectively
Klonoff-Cohen et al[43] 1989	Case control	110 preeclamptic cases 115 normotensive controls	Contraceptive and reproductive history of subjects	OR for preeclampsia for barrier contraceptive users was 2.37 (95%CI: 1.01-5.58)
Mills et al[44]	Merge data from two prospective cohort studies	13914 pregnancies (total)	Incidence of preeclampsia	OR for preeclampsia in barrier contraceptive users were 0.85 (95%CI: 0.71-1.12) (one study) and 0.85 (95%CI: 0.49-1.45) (second study)
Saftlas et al[46]	Case control	258 cases 182 controls	Length of sexual cohabitation	OR for preeclampsia among women with long (> 90%) sexual relation-OR = 0.3 (95%CI: 0.1-0.9)

PIH: Pregnancy induced hypertension.